how to use fbconnect in java

i want to allow my users to register in my site by using facebook account by gathering info from facebook server. but i did not know how can i start please some one help me.....

Thanks in adavance

As far as I know,Facebook provides the login button.Plug it the way you want it.

Check developers.facebook.com

But again I am not sure if they can provide you with all the information you need.I think they provide basic information to other apps.